1. Field of the Invention
The present invention relates to a coil component used as a choke coil or a transformer (e.g., a resonance transformer used in a resonance type power supply), etc.
2. Description of the Related Art
From the point of view of lowering height, there are some cases where a choke coil or a transformer in a power supply of flat panel televisions etc is mounted on a printed circuit board, with a part thereof in an aperture of the printed circuit board. The first patent document, Japanese Patent Application Laid-Open No. 2001-57310 relates to a transformer which is simply mounted on the board or a part of which is in an aperture of the board. The first patent document says that the transformer has no conduction fault, because a part of each terminal is like spring or because the terminals are partially thin to be springy so that the terminal and the board steadily touch each other when the transformer is mounted on the board.
In the case where the terminals are partially springy like the transformer in the first patent document, even if the terminal and the board steadily touch each other, there is a problem that a connection between the terminals and the board is easy to be cut off because force of vibration or shock after soldering is applied to the soldering part connecting the terminals and the board. Another problem is that whole weight of the transformer should be supported by the terminals, which applies much force to the terminals. Moreover, there is a problem that mounting condition of the transformer is so unstable that accuracy of height is bad.
The second patent document, Japanese Patent Application Laid-Open No. 2001-307922 relates to a method of mounting a coil element, in which a winding is directly given to a drum core, in an opening of a printed circuit board. However, the second patent document cannot solve above problems of the transformer like the first patent document which uses bobbin in addition to a magnetic core and in which winding ends are bound to terminals fitted to the bobbin.